3-4 pieces (they vary in size) should do it. Handle with gloves, best to put in a paper bag or a "sleeve" to prevent contact with other items, especially produce. Wet burlap or heavy cotton material (rug, etc) on top of chest plus white or reflective ice chest cover helps. Open as little as possible and move items, drain water, etc. in the relative cool of the AM or PM. Have a great trip!
"If you understand, things are just as they are; if you do not understand, things are just as they are."